1. Field of the Invention
This invention relates to a photosensitive composition, and more specifically, to a photosensitive composition containing a .beta.-diketonato-metal chelate compound as an image-forming material.
2. Description of the Prior Art
A number of photographic materials are presently known which provide stable images directly by exposure, or which form latent images by exposure and provide stable developed images by chemically or physically treating the latent images. Furthermore, many reversible photographic materials are known which provide images directly by exposure, but in which the images are erased upon standing at room temperature or heating and the images changed or new images formed by additional exposure (i.e., photochromic materials). The materials used as a photosensitive material or an image-forming material in these photographic materials include inorganic compounds, organic compounds and organic acid metal salts as well as elemento-organic compounds such as organo-metallic compounds.
Inorganic compounds include, for example, metal halides such as silver halides. Of these, non-silver salts are described in detail in J. Kosar, Light-Sensitive Systems, John Wiley & Sons, (1965). As organic compounds, diazo compounds, photopolymers and free radical generating photographic materials are known, the first two being described in detail in Kosar, supra. Photographs generated using free radicals are obtained by a photographic process which uses a polyhalogenated hydrocarbon capable of generating free radicals due to the action of light such as carbon tetrabromide and an amine such as diphenyl amine capable of forming a dye upon reaction with free radicals or a compound contributing to the formation of an image as a result of the simultaneous occurrence of a polymerization reaction and color formation, such as N-vinyl carbazole, for example, as described in detail in R. H. Sprague, Phot. Sci. & Eng., Vol. 5, page 298, ibid., Vol. 8, pages 91 and 95 and ibid., Vol. 9, page 133, and U.S. Pat. Nos. 3,042,517 and 3,042,519. Metal salts of an organic acid include, for example, a dry silver material in which silver behenate is used as an image-forming substance and silver bromide is used as a photo-catalyst, for example, as described in detail in Japanese Patent Publication Nos. 2096/63, 4921/68 and 4924/68. Recently, a photographic material using an elemento-organic compound containing a chalcogen element (directly) bonded to an organic compound (for example, as disclosed in Japanese Laid-Open Patent Publication No. 29438/73) has been developed. Photochromic materials are described in detail in Kosar, supra.
These various photographic materials have their own advantages and disadvantages.
Silver halide photographic materials have found wide applications because of their high sensitivity, but have the disadvantage that they need complicated wet developing and fixing operations and the cost of production is high because silver is used. Diazo photographic materials, on the other hand, are less expensive, but generally require wet development using an alkali. Even in the case of dry heat-developable diazo photographic materials, the generation of an alkali is necessary. Vesicular photographic processes using diazo compounds are dry processes which do not require an alkali, but since there is no formation of color, such processes are used only for photographic materials for transparencies. Photopolymers require wet development, and since color formation does not occur, they are difficult to use for general photographic processes. Photographic materials in which free radical generating materials are used are generally of the dry type, but mostly have disadvantages with respect to their sublimability, toxicity and stability. Furthermore, the resulting images are generally unstable, and in many cases, difficult to fix.
Photographic processes using the above-described dry silver and elemento-organic compounds respectively are known as photographic processes in which development is performed in the dry state, for example, by heating, and in which the disadvantages of the radical photographic process have been eliminated to no small extent. The former has the advantage that development can be carried out in the dry state and fixation is not required, but on the other hand, suffers from the disadvantage that it is difficult to use for transparent images because expensive silver is used and the photographic material is a crystal dispersion system. The latter can be developed in the dry state, but fixation is difficult. In addition, the compound used for this photographic material is susceptible to hydrolysis, and the toxicity of some of the chalcogens also poses a problem.